Combined concurrent treatment with two or more hypolipidaemic agents is a modern trend in the pharmacotherapy of hyperlipoproteinaemias. Aggressive treatment of hyperlipoproteinaemias can lead not only to the arrest of progression but also to regression of the atherosclerotic process. The authors submit experience assembled with the treatment of 14 heterozygotes with familial hypercholesterolaemia by a combination of colestipol (Colestid Upjohn, Belgium) with gemfibrosil (Loped Parke-Davis, USA), 15 g and 1200 mg resp. per day. One month of administration of this combination of hypolipidaemic agents led to a drop of total cholesterol by 21% and of LDL-cholesterol by 30%. At the same time the authors recorded a marked and statistically significant increase of HDL-cholesterol by 23%. Favourable changes were observed also as regards apolipoprotein concentrations. The apolipoprotein A-1 level increased by 32%, while the level of the atherogenic apolipoprotein B declined by 30%. The triglyceride level declined also. It did not prove possible even by combined treatment to reduce the level of apolipoprotein(a). Combined treatment with colestipol and gemfibrosil was well tolerated by the patients and in none of the patients treatment had to be discontinued because of undesirable side-effects.